Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

An image-capturing device configured for an optical pointing apparatus
includes a plurality of image-sensing units arranged adjacently. The
plurality of image-sensing units are configured to sense images of a
surface and generate sensing signals that are used for evaluating the
velocity of the optical pointing apparatus. The image-capturing device is
configured to use different image-sensing units arranged differently to
sense the surface according to the velocity of the optical pointing
apparatus. When the optical pointing apparatus moves at a first velocity,
the image-capturing device uses the image-sensing units configured to
occupy a smaller area to sense the surface. When the optical pointing
apparatus moves at a second velocity, the image-capturing device uses the
image-sensing units configured to occupy a larger area to sense the
surface. The first velocity is lower than the second velocity.

Claims:

1. An image-capturing device configured for an optical pointing
apparatus, comprising: a plurality of adjacently arranged image-sensing
units configured to sense an image of a surface and generate a sensing
signal being adapted to evaluate a velocity of the optical pointing
apparatus; wherein the image-capturing device uses different arrangements
of the image-sensing units to sense the image of the surface according to
different velocities of the optical pointing apparatus; wherein when the
optical pointing apparatus moves at a first velocity, the image-capturing
device uses image-sensing units configured to occupy a smaller area to
sense the surface, and when the optical pointing apparatus moves at a
second velocity, the image-capturing device uses image-sensing units
configured to occupy a larger area to sense the surface, wherein the
first velocity is lower than the second velocity.

2. The image-capturing device of claim 1, wherein when the optical
pointing apparatus moves at the first velocity, the image-capturing
device is configured to use a field of first dimension to sense the
surface, and when the optical pointing apparatus moves at the second
velocity, the image-capturing device is configured to use a field of
second dimension to sense the surface, wherein the field of first
dimension is smaller than the field of second dimension.

3. The image-capturing device of claim 2, further comprising: a memory
device configured to store sensing signals generated by the image-sensing
units; and a processing unit configured to compare sensing signals stored
in the memory device with sensing signals generated by the image-sensing
units to compute a distance of movement of the optical pointing apparatus
and to select the field of first dimension or the field of second
dimension according to the distance.

4. The image-capturing device of claim 3, wherein the processing unit is
configured to determine the velocity of the optical pointing apparatus by
a computed horizontal or vertical displacement.

5. The image-capturing device of claim 4, wherein when the horizontal
displacement computed by the processing unit is less than a first
horizontal threshold and the vertical displacement computed by the
processing unit is less than a first vertical threshold, the processing
unit determines that the optical pointing apparatus moves at the first
velocity, and when the horizontal displacement is greater than a second
horizontal threshold or the vertical displacement is greater than a
second vertical threshold, the processing unit determines that the
optical pointing apparatus moves at the second velocity.

6. The image-capturing device of claim 1, wherein the image-sensing units
configured to sense the surface by all of the image-sensing units when
the optical pointing apparatus moves at the second velocity.

7. The image-capturing device of claim 1, wherein the image-sensing units
configured to occupy a smaller area correspond to a portion of
image-sensing units arranged adjacent to each other when the optical
pointing apparatus moves at the first velocity.

8. The image-capturing device of claim 1, wherein when the image-sensing
units are configured to occupy a larger area to sense the surface, a
pixel of sensing signal generated by the image-capturing device is
generated by a combination of pixel information from a plurality of
adjacent image-sensing units.

9. The image-capturing device of claim 1, wherein when the image-sensing
units are configured to occupy a larger area to sense the surface, a
pixel of sensing signal generated by the image-capturing device is
generated by pixel information from one of a plurality of adjacent
image-sensing units.

10. The image-capturing device of claim 8, wherein a binning technique is
employed to obtain the combination of pixel information from the
plurality of adjacent image-sensing units.

11. The image-capturing device of claim 1, wherein the image-sensing
units have a same dimension.

12. The image-capturing device of claim 1, wherein within the plurality
of adjacently arranged image-sensing units, a dimension of the
image-sensing units in a middle region is less than that of the
image-sensing units in a circumambient region.

13. The image-capturing device of claim 1, wherein within the plurality
of adjacently arranged image-sensing units, a dimension of the
image-sensing units in a middle region is greater than that of the
image-sensing units in a circumambient region.

14. An image-capturing device configured for an optical pointing
apparatus, comprising: a plurality of adjacently arranged image-sensing
units configured to sense an image of a surface and generate a sensing
signal being adapted to evaluate a velocity of the optical pointing
apparatus; wherein the image-capturing device uses different arrangements
of the image-sensing units to sense the image of the surface according to
velocities of the optical pointing apparatus; wherein when the optical
pointing apparatus moves at a first velocity, the image-capturing device
is configured to use a plurality of image-sensing units with high
count-per-inch resolution to sense the surface, and when the optical
pointing apparatus moves at a second velocity, the image-capturing device
uses a plurality of image-sensing units with low count-per-inch
resolution to sense the surface, wherein the first velocity is lower than
the second velocity.

15. The image-capturing device of claim 14, wherein when the optical
pointing apparatus moves at the first velocity, the image-capturing
device is configured to use a field of first dimension to sense the
surface, and when the optical pointing apparatus moves at the second
velocity, the image-capturing device is configured to use a field of
second dimension to sense the surface, wherein the field of first
dimension is smaller than the field of second dimension.

16. The image-capturing device of claim 15, further comprising: a memory
device configured to store sensing signals generated by the image-sensing
units; and a processing unit configured to compare sensing signals stored
in the memory device with sensing signals generated by the image-sensing
units to compute a distance of movement of the optical pointing apparatus
and to select the field of first dimension or the field of second
dimension according to the distance.

17. The image-capturing device of claim 16, wherein the processing unit
is configured to determine the velocity of the optical pointing apparatus
by a computed horizontal or vertical displacement.

18. The image-capturing device of claim 17, wherein when the horizontal
displacement computed by the processing unit is less than a first
horizontal threshold and the vertical displacement computed by the
processing unit is less than a first vertical threshold, the processing
unit determines that the optical pointing apparatus moves at the first
velocity, and when the horizontal displacement is greater than a second
horizontal threshold or the vertical displacement is greater than a
second vertical threshold, the processing unit determines that the
optical pointing apparatus moves at the second velocity.

19. The image-capturing device of claim 14, wherein the image-sensing
units with high count-per-inch resolution correspond to all of the
image-sensing units.

20. The image-capturing device of claim 14, wherein the image-sensing
units with low count-per-inch resolution correspond to a portion of
image-sensing units arranged adjacent to each other.

21. The image-capturing device of claim 14, wherein when the
image-sensing units with high count-per-inch resolution are used to sense
the surface, a pixel of sensing signal generated by the image-capturing
device is generated by a combination of pixel information from a
plurality of adjacent image-sensing units.

22. The image-capturing device of claim 14, wherein when the
image-sensing units with high count-per-inch resolution are used to sense
the surface, a pixel of sensing signal generated by the image-capturing
device is generated by pixel information from one of a plurality of
adjacent image-sensing units.

23. The image-capturing device of claim 21, wherein the combination of
pixel information from the plurality of adjacent image-sensing units is a
combination of analog or digital signals of pixel information captured
from the plurality of adjacent image-sensing units.

24. The image-capturing device of claim 14, wherein the image-sensing
units have a same dimension.

25. The image-capturing device of claim 14, wherein within the plurality
of adjacently arranged image-sensing units, a dimension of the
image-sensing units in a middle region is less than that of the
image-sensing units in a circumambient region.

26. The image-capturing device of claim 14, wherein within the plurality
of adjacently arranged image-sensing units, a dimension of the
image-sensing units in a middle region is greater than that of the
image-sensing units in a circumambient region.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is based on, and claims priority from,
Taiwan Patent Application Serial Number 100105043, filed on Feb. 16,
2011, the disclosure of which is hereby incorporated by reference herein
in its entirety.

BACKGROUND

[0002] 1. Technical Field

[0003] The present invention relates to an optical pointing apparatus, and
relates more particularly to an optical pointing apparatus comprising an
image-capturing device.

[0004] 2. Related Art

[0005] Pointing apparatuses such as an electronic mouse are devices that
can detect their displacements relative to their supporting surfaces. A
user grasps a pointing apparatus and slides the pointing apparatus on a
planar surface. The pointing apparatus may compute its displacement
relative to the planar surface, and may use the displacement as an input
signal sent to a computer. A conventional pointing apparatus may compute
its displacement according to the number of rolling cycles counted by the
roller on the apparatus as the device rolls on a surface. However,
accumulated dust may adversely affect the accuracy of the calculation of
the displacement of the roller pointing apparatus after the roller
pointing apparatus has been used for a long time. Due to such
disadvantage, with the development of technology, optical pointing
apparatuses such as the optical mouse increasingly replace such roller
pointing apparatuses.

[0006] Optical pointing apparatuses similarly detect their displacements
relative to their supporting surfaces. Unlike conventional roller
pointing apparatuses, optical pointing apparatuses detect their
displacements based on reflective light. FIG. 1 shows a conventional
optical pointing apparatus. As shown in FIG. 1, the optical pointing
apparatus 100 comprises a light source 102, a focus lens 104, a light
extraction lens 106, a sensing device 108, and a processing unit 110. The
light source 102 may be an LED (light-emitting diode) based light source
or a laser, which projects light through the focus lens 104 onto a planar
surface 150. The planar surface 150 reflects the light, and the light
extraction lens 106 collects reflective light and brings it to the
sensing device 108. The processing unit 110 uses output signals from the
sensing device 108 to calculate the displacement of the optical pointing
apparatus 100 relative to the planar surface 150.

[0007] FIG. 2 shows an enlarged sensing device 108. As illustrated in FIG.
2, the sensing device 108 comprises a plurality of image-sensing elements
200 arranged in an array. The image-sensing elements 200 may capture the
image of the planar surface 150 whereby the output signals are generated.
The processing unit 110 compares the correlation between two successive
images, and determines the displacement of the optical pointing apparatus
100 relative to the planar surface 150 by the relative orientation and
distance between two highly correlated regions. For example, if the
comparison result from the processing unit 110 shows that the second
image is highly correlated with the upper left region of the first image,
it can be determined that the optical pointing apparatus 100 is moving in
the lower right direction.

[0008] Generally, under the condition that the number of image-sensing
elements 200 is the same, if the areas of the image-sensing elements 200
are larger, the resolution of the image-sensing elements 200 is lower;
while if the areas of the image-sensing elements 200 are smaller, the
detectable displacement range is smaller. In other words, regardless
whether the areas of the image-sensing elements 200 are large or small,
the performance of the optical pointing apparatus 100 has its own
limitation. The optical pointing apparatus with large area image-sensing
units has poor resolution that causes users to experience non-smooth
cursor movements. In contrast, with optical pointing apparatus with small
area image-sensing units, the user needs to move the optical pointing
apparatus farther to obtain sufficient accuracy of desired input signals,
and the optical pointing apparatus with small area image-sensing units
leads to a smaller detectable displacement range.

[0010] Embodiments provide an image-capturing device that is configured
for an optical apparatus and has the advantages of both optical pointing
apparatus with large and small area image-sensing units so as to meet
different usage requirements.

[0011] In one embodiment, an image-capturing device configured for an
optical pointing apparatus comprises a plurality of adjacently arranged
image-sensing units. The plurality of adjacently arranged image-sensing
units are configured to sense an image of a surface and generate a
sensing signal that is adapted to evaluate a velocity of the optical
pointing apparatus. The image-capturing device uses different
arrangements of the image-sensing units to sense the image of the surface
according to different velocities of the optical pointing apparatus. When
the optical pointing apparatus moves at a first velocity, the
image-capturing device uses image-sensing units configured to occupy a
smaller area to sense the surface; and when the optical pointing
apparatus moves at a second velocity, the image-capturing device uses
image-sensing units configured to occupy a larger area to sense the
surface, wherein the first velocity is lower than the second velocity.

[0012] In another embodiment, an image-capturing device configured for an
optical pointing apparatus comprises a plurality of adjacently arranged
image-sensing units. The plurality of adjacently arranged image-sensing
units are configured to sense an image of a surface and generate a
sensing signal that is adapted to evaluate a velocity of the optical
pointing apparatus. The image-capturing device uses different
arrangements of the image-sensing units to sense the image of the surface
according to different velocities of the optical pointing apparatus. When
the optical pointing apparatus moves at a first velocity, the
image-capturing device is configured to use a plurality of image-sensing
units with high count-per-inch (CPI) resolution to sense the surface; and
when the optical pointing apparatus moves at a second velocity, the
image-capturing device uses a plurality of image-sensing units with low
count-per-inch resolution to sense the surface, wherein the first
velocity is lower than the second velocity.

[0013] To better understand the above-described objectives,
characteristics and advantages of the present invention, embodiments,
with reference to the drawings, are provided for detailed explanations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will be described according to the appended drawings
in which:

[0015] FIG. 1 shows a conventional optical pointing apparatus;

[0016] FIG. 2 shows an enlarged sensing device;

[0017]FIG. 3 is a view showing an image-capturing device configured for
an optical pointing apparatus according to one embodiment of the present
invention;

[0018]FIG. 4 is an enlarged view showing image-sensing units according to
one embodiment of the present invention;

[0019]FIG. 5 is a flow diagram showing the steps of a method of
calculating the displacement of an optical pointing apparatus according
to one embodiment of the present invention; and

[0020]FIG. 6 is an enlarged view showing image-sensing units of an
image-capturing device according to another embodiment of the present
invention.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

[0021] In the following detailed description, for purposes of explanation,
numerous specific details are set forth in order to provide a thorough
understanding of the disclosed embodiments. It will be apparent, however,
that one or more embodiments may be practiced without these specific
details. In other instances, well-known structures and devices are
schematically shown in order to simplify the drawing.

[0022]FIG. 3 is a view showing an image-capturing device configured for
an optical pointing apparatus according to one embodiment of the present
invention. Referring to FIG. 3, the image-capturing device 300 can be
installed in an optical pointing apparatus 350 and comprises a plurality
of image-sensing units 302 arranged adjacently, a memory device 304, and
a processing unit 306. The optical pointing apparatus 350 can slide
relative to a planar surface 360. The image-sensing units 302 are
configured to sense images of a surface and to generate sensing signals
that can be used to evaluate the velocity of the optical pointing
apparatus 350. The memory device 304 is configured to store the sensing
signals generated by the image-sensing units 30. The processing unit 306
is configured to compare the sensing signals stored in the memory device
304 with the sensing signals generated by the image-sensing units 302 to
compute the distance of the movement of the optical pointing apparatus
350.

[0023]FIG. 4 is an enlarged view showing image-sensing units 302
according to one embodiment of the present invention. As shown in FIG. 4,
the central region of the image-sensing units 302 comprises 256
image-sensing units 402 with small areas. The circumambient region of the
image-sensing units 302 comprises 192 image-sensing units 404 with large
areas, wherein the area of each image-sensing unit 404 is equal to 4
times the area of the image-sensing unit 402.

[0024] Referring to FIG. 3 again, the image-capturing device 300 may use
different image-sensing units 302 to capture the image of the planar
surface 360 by different velocities of the optical pointing apparatus
350. For example, when the optical pointing apparatus 350 moves at a
first velocity, the image-capturing device 300 may be configured to use
the small-area image-sensing units 402 to capture the image of the planar
surface 360; whereas when the optical pointing apparatus 350 moves at a
second velocity, the image-capturing device 300 may be configured to use
the large-area image-sensing units 404 to capture the image of the planar
surface 360, wherein the first velocity is lower than the second
velocity. The small-area image-sensing units 402 constitute a sensing
field of small dimension, and the image-capturing device 300 is
configured to use the sensing field of small dimension to sense the
surface 360 when the optical pointing apparatus 350 moves at a low
velocity. Similarly, the image-capturing device 300 is configured to use
the sensing field of large dimension to sense the surface 360 when the
optical pointing apparatus 350 moves fast. When a user moves the optical
pointing apparatus 350 slowly, the user most likely expects more precise
computer input signals, and the high resolution provided by the sensing
field of small dimension constituted by the small-area image-sensing
units 402 can meet such expectation. When a user moves the optical
pointing apparatus 350 fast, the sensing field of large dimension
constituted by the large-area image-sensing units 404 can provide the
capability to rapidly track the motion trajectory of the optical pointing
apparatus 350. Therefore, the image-capturing device 300 may provide
different sensing solutions according to different application
conditions.

[0025] In another embodiment of the present invention, the image-sensing
units 302 comprise high spatial resolution and low spatial resolution
image-sensing units. When a user moves the optical pointing apparatus 350
at a slow velocity, the image-capturing device 300 employs the high
count-per-inch (CPI) image-sensing units 302 to capture the image of the
surface 360. When a user moves the optical pointing apparatus 350 at a
high velocity, the image-capturing device 300 employs the low CPI
image-sensing units 302 to capture the image of the surface 360.

[0026]FIG. 5 is a flow diagram showing the steps of a method of
calculating the displacement of an optical pointing apparatus according
to one embodiment of the present invention, wherein the calculating
method can be applied to the processing unit 306. In Step 501, an optical
pointing apparatus is employed to sense a surface to generate a first
image signal, and the method then proceeds to Step 502. In Step 502, the
optical pointing apparatus is employed to sense a surface to generate a
second image signal, and the method proceeds to Step 503. In Step 503,
the displacements of the optical pointing apparatus along the vertical
and horizontal directions are computed according to the first and second
image signals, and the method proceeds to Step 504. In Step 504, it is
determined whether the optical pointing apparatus is in a high-velocity
condition. If yes, the method proceeds to Step 505; otherwise the method
proceeds to Step 506. In Step 505, the horizontal displacement and the
vertical displacement of the optical pointing apparatus are compared with
thresholds. If the horizontal displacement of the optical pointing
apparatus is less than a first horizontal threshold and the vertical
displacement of the optical pointing apparatus is less than a first
vertical threshold, the method proceeds to Step 507; otherwise, the
method proceeds to Step 508. In Step 506, the horizontal displacement and
the vertical displacement of the optical pointing apparatus are compared
with thresholds. If the horizontal displacement of the optical pointing
apparatus is greater than a second horizontal threshold or the vertical
displacement of the optical pointing apparatus is greater than a second
vertical threshold, the method proceeds to Step 508; otherwise, the
method proceeds to Step 507. In Step 507, the current condition is
determined as a low velocity condition, a sensing field of small
dimension is employed as the operative sensing field of the optical
pointing apparatus, and the method proceeds to Step 509. In Step 508, the
current condition is determined as a high-velocity condition, a sensing
field of large dimension is employed as the operative sensing field of
the optical pointing apparatus, and the method proceeds to Step 509. In
Step 509, it is determined whether the method is finished. If yes, the
method is terminated; otherwise, the method returns to Step 501.

[0027]FIG. 6 is an enlarged view showing image-sensing units 600 of an
image-capturing device according to another embodiment of the present
invention. As shown in FIG. 6, the central region of the image-sensing
units 600 comprises 256 small area image-sensing units 602. The
circumambient region of the image-sensing units 600 comprises 192 large
area image-sensing units 604. The middle region between the small area
image-sensing units 602 and the large area image-sensing units 604
comprises 192 medium area image-sensing units 606. With this arrangement,
the image-sensing units 600 can, in response to the velocity of the
image-capturing device, employ the image-sensing units 602, 604 and 606
with different dimensions to provide high resolution or low resolution
sensing fields.

[0028] The image-sensing units of the image-capturing device of the
present invention are not limited to the arrangement in which the small
area image-sensing units are in the central region and the large area
image-sensing units are in the circumambient region. In some embodiments
of the present invention, the dimensions of the image-sensing units in
the central region are larger than those of the image-sensing units in
the circumambient region, and in other embodiments of the present
invention, the image-sensing units can all be equal in size. The
image-capturing device of the present invention is not limited to an
image-capturing device in which each output pixel corresponds to the
output pixel information from an image-sensing unit. When the
image-capturing device of the present invention is configured to use
large-area or low CPI sensing field to sense a surface, each pixel of
sensing signal generated by the image-sensing units can be formed by
combining pixel information captured from a plurality of adjacent
image-sensing units, wherein the combination of the pixel information
from the plurality of adjacent image-sensing units can rely on binning
techniques. In another embodiment of the present invention, when the
image-capturing device of the present invention is configured to use a
large-area or low CPI sensing field to sense a surface, each pixel is
generated according to the pixel information from one of a plurality of
adjacent image-sensing units.

[0029] In summary, an image-capturing device configured for an optical
pointing apparatus can use different arrangements of image-sensing units
to capture an image of a surface according to the velocity of the optical
pointing apparatus. Therefore, the image-capturing device can track the
movement of the optical pointing apparatus with sufficient CPI and
without increasing image-sensing unit areas.

[0030] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed embodiments. It
is intended that the specification and examples be considered as
exemplary only, with a true scope of the disclosure being indicated by
the following claims and their equivalent.